Making work old Darksoft multis with code injection on all 93646B-3 boards

[Tailsnic Retroworks]

@Darksoft Hi. I have just discovered a solution for a mysterious issue with installing old multis on 93646B-3 boards. The problem is, after updating the bootloader with STM32 and flashing the new image update via SD, the code injection of the games doesn't work even using good quality cables and installing the 4.7k resistor between DATA and GND in the corner as other boards have.

Only phoenixized games like The Punisher, Final Fight Anniversary or SSF2X Freeplay would work, but not original ones with code injection.

Is it known that there were a few 93646B-3 counted with the fingers that had this problem (a complete mystery), and I have had the incredible luck of finding one (@Viku 's one, xD).

So, this is the solution I have used and works very good. Following this image reference of old Darksoft multis (IGNORE SWD5):

You have to use these alternate points:

CLK and SETUP1 are easy to catch because 2 resistors have it with good access
SETUP2 is a hole through VIA
SETUP1 also is a hole through VIA, and you have to solder to it a 4.7K resistor to GND (using the GND leg of a ram)

Cut the cables as short as you can, and you will make it perfectly working with code injection.

 

[Viku]

 

[Darksoft]

Fantastic news. I wonder what @l_oliveira will say...

 

[l_oliveira]

As I said privately to Darksoft on discord, this must have to do with the long traces that come from the CIF custom IC and go through the board up to the CN2 on the opposite side of the board.

 

[Tailsnic Retroworks]

As I said privately to Darksoft on discord, this must have to do with the long traces that come from the CIF custom IC and go through the board up to the CN2 on the opposite side of the board.

There can be a big time delay applying cables.

It's a double way, so must be that. Even using AWG30 Kynar cables didn't make the trick. That's why on B-3 boards the Infinikey works, because is installed just in the natural corner of the pin points, so its data transfer it's "natural" using only the PCB traces.